Explosion safety device



Aug. 29, 1939. YH. BRUNING Y 2,170,937

` EXPLOSION SAFETY DEVICE Filed July 28, 19:57 2 sheets-Sheet 1 Figi.

Aug 29, 1939- H. BRUNING EXPLOSION SAFETY DEVICE Filed July 28, 1937 2 Sheets-Sheet 2 Patented Aug. 29, 1939 UNITED STATES EXPLOSION SAFETY DEVICE Hans Brning, Hanau-on-the-Main, Germany,

assigner to W. C. Heraeus, G. m. b. H., Hanauon-the-Main, Germany Application July 28, 1937, Serial No. 156,187 In Germany July 29, 1936 6 Claims.

The present invention relates to an improvement in heat-insulated enclosures which are exposed to the danger of explosion.

The subject of the invention is an arrangement 5 for safeguarding, as much as possible, the surroundings of these enclosures against the consequences of explosions, without impairing the good heat insulation of the enclosures.

The heat-insulated enclosures according to the present invention are provided with a safety arrangement Which is used in the case of an explosion, which comprises a wall consisting of several thin easily broken layers which reflect heat radiation and which are arranged one behind the other in a strong frame.

The invention has application to enclosures of widely ydifferent kinds, such as drying cabinets, chambers, channels and rooms for dangerous explosive materials, for instance, lacquer drying cabinets and, furthermore, to containers and entire workrooms in the explosives industry and in the industry of aluminium powder manufacture. The enclosures may be unheated or may be heated, for instance, electrically. Protection against weather conditions, when equipping entire workrooms with the new device, is preferably effected by thin rainproof skin-s.

Referring to the two sheets of drawings accompanying the specication,

Fig. l is a View in perspective of an incubator or oven, with the wall partially broken away, to show lthe structure;

Fig. 2 is a fragmentary elevational view in partial section, showing the structure of a side panel;

Fig. 3 is a view similar to Fig. 2 of another panel construction;

Fig. 4 is a view similar to Fig. 2 of another panel construction;

Fig. 5 is a view in perspective of an oven or enclosure embodying the invention;

Fig. 6 is a fragmentary view in perspective, and in partial section, of another panel, illustrating a modified form of panel;

Fig. l is a view similar to Fig. 6 of another modification, having perforated walls;

Fig. 8 is a similar view of another modification, having cutting members 32, for facilitating `the breakage of the walls;

Fig. 9 is a view in perspective of an oven or:

enclosure embodying any of the panels of Figs. 6, 7, and 8.

Fig. l shows a drying cabinet according yto the present invention. In the strong frame 5 fixed in the casing I there are located, one behind the other, several thin, easily broken layers 2 which reflect heat radiation. They may consist of thin metal skins, for instance, aluminium foils, or of thin non-metallic materials with a coating 'having a metallic lustre, for instance, Cellophane with an aluminium lacquer coating. The walls are made, if possible, of cheap materials and the arrangement is devised so that the walls can be rapidly renewed after an explosion.

One corner of the cabinet is shown broken away in Fig. 1 in order to show the layer assembly. The thin layers 3 arranged one behind the other can be seen. In the case illustrated, the two outer layers 3 are flat while the inner layers 4 are crimped.

In Fig. l, furthermore, the heating arrangement 6 of the drying cabinet, the perforated charging plate l, the flue 8, the door 9 and the usual heat insulation of the casing wall I can be seen.

Fig. 2 shows in perspective a Inpded form of wall constructed according to the invention for use on enclosures exposed to danger of explosion, for instance lacquer drying cabinets. The wall comprises several separate panels bounded by the frame I5, in which the thin layers I3, I4 are located. The frame is mounted in an aperture in the wall, which is filled in the usual manner with insulating material l I, of the enclosure. The outer layers i3 are flat and the inner layers Ill are crimped.

In the` part of the.wall which is again particu.- larly illustrated in Fig. 3, the iiat outer layers are shown at I6 and the crimped inner layers at Il.

Instead of using irregularly crimped layers, pleated may also be employed. The part of a wall which is illustrated in Fig. 4. shows two thin flat outer layers I8, between which are arranged a plurality of thin pleated layers I9.

Alternatively, all the layers, both external and internal, may be flat, as shown by the layers 3i) in Fig. 8.

Any -desired number of layers may be used depending upon whether greater importance is attached to the protection against explosion or to the heat protection.

According to the circumstances, a part of a wall, a whole wall, several walls or all walls of the enclosure are constructed in the new manner according to the invention. In Fig. l discussed above, a drying cabinet is illustrated in which a wall is almost completely filled by the frame carrying the thin layers. In Fig. 5 a drying cabinet is illustrated in` which only a part of the wall is provided with the new safety measure. In this figure, 22 is the frame iixed in the cabinet casing 20 and carrying the wall 2l consisting of a number of thin, easily broken layers which reflect heat radiation.

Small walls may be enclosed as a whole in a frame, While large walls are preferably divided into smaller panels as shown, for example in Fig. 2.

For the thin layers, heat radiation-reiiecting materials which easily break are employed. The breaking may, in addition, be -promotedA by rnechanical auxiliary means, several examples of which will now be described.

If more than two thin layers are employed, the inner layers, independently of whether they are flat, pleated, or crimped, may be pre-cut in any desired manner by dividing incisions. The result is thereby obtained that only the two outer layers must be broken by the explosive force, while the prepared inner layers offer a negligibly small resistance to breakage. An example is' illustrated in Fig. 6 which shows the construction of a wall according to this feature of the invention. The flat outer layers 23 and the crimped inner layers 24 are shown, the latter being divided into smaller parts by dividing incisions 25.

An alternative means of increasing the breaking property of the thin intermediate layers consists in weakening the latter at preferred points. This may be achieved, for instance, by reducing the thickness of the layer, by sharply kinking it, or by perforating it. An example of this is illustrated in Fig. 7, in which the wall, comprises the flat outer layers 26 and the crimped inner layers 21, which latter are so weakened by holes 28 arranged in any desired rows that they present no resistance to an explosive force and easily break along these lines.

Since, under the action of the explosive force, the surfaces which are to be broken rst bulge outwards, the breaking may be promoted or assisted by mechanical auxiliary means, for in.- stance by providing narrow-edged objects, wires or the like which extend or are stretched adjacent the outer surface of the wall and right across its width, in such a way that in the case of an explosion, they cut through the thin-walled layers like a knife. An example of such an arrangement is illustrated in Fig. 8, in which the thin layers 30, arranged within the frame 3|, constitute the multi-layer wall, on one side of which sharp-edged lattice-bars 32 are arranged which, in the case of an explosion, cut through the individual layers like a knife.

The above-described means are suitable individually or in any combination, for substantially reducing the resistance to breaking of safety Walls consisting of several thin layers.

In cabinets exposed to danger of explosion which are provided with the safety arrangement described, it is desirable to make the door very strong and to secure it so rmly by means of stays, crossbars or the like mounted across its front, that the pressure produced by an explosion is reduced by the breaking of the light walls. An example of such a cabinet is illustrated in Fig. 9. In the frame 34, xed in the cabinet casing 33, several thin easily broken layers 35 which reflect heat radiation are arranged one behind the other. The cabinet door 36 is additionally secured by two separate strong stay bolts 3l. The opening and closing of the door may, if desired, be effected, by lever devices from a remote point.

It should be emphasized that the invention is not restricted to the examples illustrated. Further obvious forms of execution of the invention may occur to the expert.

The new heat-insulated enclosures exhibit considerable technical advantages. Enclosures and chambers exposed to danger of explosion are, as is well-known constructed as light as possible in order that they will yield easily on the occurrence of an explosion, and allow a balance of pressure. If it is a question, however, of enclosures which, in addition must have a good heat insulation, then with the usual insulation materials such as cork walls, Wood, slag Wool and the like and the arrangements necessary for their fixation, masses result which either do not yield sufficiently easily on the occurrence of an explosion or do damage on being thrown off. The invention solves the problem of eliminating as far as possible the consequences of an explosion, such as are manifested in the hurling-off of wall parts, without impairing the heat protection. The safety obtained with the invention is much greater than if snap-doors are provided, which often open far too slowly to prevent the destruction of the chamber. In lacquer drying cabinets, it has even happened that doors left only slightly ajar have been torn from their hinges by the explosion and hurled a considerable distance. In such cases, the safety measure has immediately become a source of danger. Small explosion flaps are often not sufcient to reduce the excess pressure of an explosion while the incorporation of large explosion iiaps or the arrangement of simple, light sheetmetal doors without heat protection is usually not permissible owing to the great heat losses associated therewith and the non-uniformity of temperature caused thereby. The present invention, on the contrary, solves the problem of providing simultaneous protection against explosion and heat insulation in an excellent manner.

Moreover, the amount of heat required to heat the new cabinets according to the invention to the desired temperature is low, which renders short initial heating periods possible.

I claim:

1. In an explosion-safety heat insulated enclosure, the combination of a heat insulating chamber having bottom, top, and side walls carried by a relatively strong frame and provided with heat insulating material adapted to withstand the forces of explosion when said chamber is provided with a heat insulating safety arrangement, and a heat insulating safety arrangement comprising a portion of said enclosure and consisting of a plurality of thin metal foils arranged in a suitable frame and spaced from each other with respect to their arrangement from the inside to the outside of the chamber, said foils being characterized by the absence of intermediate lling means whereby they are adapted to be frangible upon occurrence of an explosion or excessive pressure in said chamber.

2. An explosion-safety heat insulated en closure according to claim 1, in which the innermost layers of thin metal foil are formed with dividing incisions to facilitate their breaking in the case of an explosion.

3. An explosion-safety heat insulated enclosure according to claim l, in which the inner layers of thin metal foil are weakened at predetermined points to facilitate their breaking in the case of an explosion.

4. An explosion-safety heat insulated enclosure according to claim 1, in which thin metal foils are provided with substantially plane surfaces.

5. An explosion-safety heat insulated enclosure according to claim l, in which the thin metal foils are provided with crimped surfaces.

6. An explosion-safety heat insulated enclosure according to claim l, in which the innermost thin metal foils are provided with crimped surfaces whereby they are adapted to bulge and engage and break the adjacent metal foils upon explosion.

HANS BRNING. 

